【UE4 C++ 基础知识】<4> 枚举 Enum、结构体 Struct

枚举

• UENUM宏搭配BlueprintType可以将枚举暴露给蓝图，不使用的话，仅能在C++使用

  //定义一个原生enum class
  enum class EMyType 
  {
  	Type1,
  	Type2,
  	Type3,
  };
  
  namespace EState 
  {
  	enum Type {
  		Stop,
  		Close,
  		Open
  	};
  }
  
  // 带反射枚举
  UENUM(BlueprintType)
  enum class ECurrentState : uint8
  {
  	Idle UMETA(DisplayName="空闲"),
  	Attack UMETA(DisplayName="攻击"),
  	Roll UMETA(DisplayName="翻滚"),
  	Dead UMETA(DisplayName="死亡"),
  };
  
  UPROPERTY(EditAnywhere,BlueprintReadWrite)
  	ECurrentState MyCurrentState UMETA(DisplayName = "当前状态");
  

  

• 枚举值与字符串转换, 针对 UENUM

  • .h

    UENUM()
    enum class ECultureTeam :uint8 {
    	EN = 0,
    	ZH = 1
    };
    //根据 enum 类型获取字符串
    template<typename TEnum>
    FString GetEnumValueAsString(const FString& Name, TEnum value);
    
    //根据字符串 获取 enum 值
    template<typename TEnum>
    TEnum GetEnumValueFromString(const FString& Name, FString value);
    

  • .cpp

    template<typename TEnum>
    FString DataHandle::GetEnumValueAsString(const FString& Name, TEnum value)
    {
    	const UEnum* EnumPtr = FindObject<UEnum>(ANY_PACKAGE, *Name, true);
    	if (!EnumPtr)
    		return FString("InValid");
    	return EnumPtr->GetNameStringByIndex((int32)value);
    }
    
    template<typename TEnum>
    TEnum DataHandle::GetEnumValueFromString(const FString& Name, FString value)
    {
    	const UEnum* EnumPtr = FindObject<UEnum>(ANY_PACKAGE, *Name, true);
    	if (!EnumPtr)
    		return TEnum(0);
    	return (TEnum)EnumPtr->GetIndexByNameString(value);
    }
    

  • 调用

    GetEnumValueAsString<ECultureTeam>(FString("ECultureTeam"), CurrentCulture);
    GetEnumValueFromString<ECultureTeam>(FString("ECultureTeam"), FString("EN"));
    
    

---

结构体

• BlueprintType可以将枚举暴露给蓝图

  //结构体
  USTRUCT(BlueprintType)
  struct FMyStruct
  {
  	GENERATED_BODY()
  
  	// 暴露给蓝图
  	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Test Variables")
  	int32 MyIntegerMemberVariable;
  
  	// 不暴露给蓝图
  	int32 NativeOnlyMemberVariable;
  
  	// 蓝图图表无法访问此UObject指针，但是指针对UE4的反射、智能指针和垃圾回收系统可见。
  	UPROPERTY()
  	UObject* SafeObjectPointer;
  };
  
  UPROPERTY(EditAnywhere,BlueprintReadWrite)
  	FMyStruct MyStruct;
  

  

• 继承FTableRowBase之后可以用于DataTable

  struct FInventoryItemInfo : public FTableRowBase
  {
  	GENERATED_BODY()
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		FString ItemName UMETA(DisplayName="名称");
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		int32 index UMETA(DisplayName="编号");
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		bool bCanStaking UMETA(DisplayName="可否叠加");
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		int32 Count UMETA(DisplayName="数量");
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		UTexture2D* Icon UMETA(DisplayName="图标");
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		TSubclassOf<AActor> ItemClass;
  
  	UPROPERTY(EditAnywhere, BlueprintReadWrite)
  		USkeletalMesh* SkeletalMesh;
  };
  
  UPROPERTY(EditAnywhere,BlueprintReadWrite)
  	FInventoryItemInfo EmptyItem;
  

  

参考

结构体